It can be desirable for high frequency electrostatic damage (ESD) protectors to have short physical lengths. ESD protector solutions based on slotted semi-rigid coaxial cable structures, such as shown in FIG. 1, can meet the required performance requirements for high frequency. When applying the structure of FIG. 1, however, to build a short cable length design, as seen in FIG. 2, a high failure rate was encountered during testing and handling of the short cable lengths.
The ESD protection device 100 as shown in FIG. 1 was proven effective for long semi-rigid coaxial cables. The ESD protection device 100 includes active components in active component slots 102. When a cable is connected to the ESD protection device 100, the inner conductor (not shown) attached to the active component does not rotate when the cable is connected due to the bend in the EDS protection device, seen in FIG. 1.
A very high failure rate was found when the cable length was shortened and the bent section removed to fit the form factor requirements of a sampling oscilloscope product line such as an external time-domain reflectometer (TDR) module protector. The shortened ESD protection device 200 fails because the fragile active components in active component slots 102 are torn apart due to a center cable conductor of the ESD protection device 200 is rotated from its original position, which tears the active components in the active component slots 102. A shortened cable does not have enough PTFE, or Teflon, to hold the center conductor in place. As a result, the cable center conductor will rotate along with the soldered on connector center pin as it rotated by a user. Rotation of this center conductor drags one of the attached arms of the active components in the active components slot 102 and rips them apart because each of the active components' arms are still attached to the stationary outer conductor. It turns out that center pin rotation on SMA (SubMiniature version A) style high frequency connectors has historically been a problem and troubled the industry for some time. The triggering action is that users usually often inadvertently rotate the body of the mating parts instead of just rotating the connector coupling nut as the user should when engaging the connectors. This causes the active components in the active component slots 102 to tear in the shortened ESD protection device 200. As discussed above, the bend shown in FIG. 1 protects the inner conductor in the longer ESD protection device 100 from being rotated and damaging its installed active components.
Accordingly, a need remains for an ESD protection device 200 which is short in length and does not include the bend of the ESD protection device 100, but that prevents tearing of the active components in the active component slots 102 when connected to a cable.